Wheel spider

ABSTRACT

A wheel with a rim as well as a wheel spider, where the wheel spider has a hub and spokes. The wheel includes spokes including one or more linearly stretched textile strands as reinforcement material of a fiber composite and each linearly stretched textile strand runs at least once from the rim to the hub and back without interruption and thus forms at least one spoke. The textile strands are connected in a positive-locking manner and/or in substance with the hub and the rim. A process is provided for the manufacture of the wheel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional under 37 CFR 1.53(b) of pending priorapplication Ser. No. 14/363,157 filed Jun. 5, 2014, which is an UnitedStates National Phase application of International ApplicationPCT/EP2012/074185 filed Dec. 3, 2012 and claims the benefit of priorityunder 35 U.S.C. § 119 of German Patent Application DE 10 2011 087 938.2filed Dec. 7, 2011. The entire contents of each application is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a wheel spider, for wheels, especially ofautomobiles, which has spokes made of fiber composite. Further, a methodfor the manufacture of such a wheel spider is disclosed.

BACKGROUND OF THE INVENTION

A common wheel design has a well, which consists of a rim well and thewheel flanges. The wheel flanges circulate the rim well on both sides,overlap this rim well and offer the tire lateral support. The wheelspider or wheel disk is used for fastening the wheel. Thereby, a wheelspider has spokes or other connections from the rim to the hub, which isarranged in the center of the wheel. A wheel disk performs the same taskwithout spokes, as an all-over connection of the rim to the hub.

It is a constant endeavor to reduce the weight of motor vehicles,especially of the unsprung masses, in the further development ofautomobile technology. The use of lightweight materials, especially offiber composites, is offered for this.

There is already a number of approaches to contribute to weightreduction by means of substituting metal spokes with fiber composites.However, in these substitutions, stability requirements may not fadeinto the background.

U.S. Pat. No. 4,681,647 suggests connecting a metallic hub with aring-shaped surrounding element. Thereby, the hub is wound around withlong reinforcement fibers, which run between the hub and the outer ring,or the hub has pin-like elevations for this, around which thereinforcement fibers are placed and then led to the outer ring. Theouter ring is itself wound around one or more times, whereupon thereinforcement fiber is led back to the hub. Another embodiment alsoprovides on the outer ring pin-like elevations, which arecorrespondingly wound around. The long reinforcement fibers have aplastic impregnation and can be hardened after the completion of thewinding between the hub and ring. They then form the spokes of thewheel. The drawback of this design is that the reinforcement fibers rununidirectionally between the hub and ring and have a low resistance tostresses parallel to the axial direction. The manufacturing process iscomplicated and time-consuming because of the complicated winding.

DE 10 2006 051 867 A1 discloses how a wheel spider consisting of aplurality of rings made of a fiber-reinforced material can beconstructed. A plurality of rings made of reinforcement fibers arefitted into the space between the rim and the hub. The rings are not yethardened and are deformed into arc-like shapes with round corners. Thecircular segment of the arc is positioned in an ideal shape at the innersurface of the rim, while the chords of the arcs are in contact witheach other and form the spokes after consolidation. The arcs areconnected in substance with each other or with the rim by means ofmatrix material. The drawback of this design is that the rings made ofreinforcement fiber material are wound unidirectionally and hence have alow resistance to forces in the axial direction. In addition, thestructure of the spokes only allows straight designs lying in the planeof the hub.

SUMMARY OF THE INVENTION

An object of the present invention is set to propose a wheel design,which connects the weight advantages of a fiber composite constructionwith a good resistance to axial stresses. A further object is to makepossible an aesthetically appealing shape of the wheel design.

This object is accomplished with a wheel spider for a wheel of thepresent invention and a process for the manufacture of such a wheel.

The wheel according to the present invention has a wheel spider, whosespokes consist of one or more linearly stretched textile strands (also:textile strands) as reinforcement material of a fiber composite. Eachlinearly stretched textile strand runs back and forth at least oncebetween the rim and the hub and thereby forms at least one spoke. Withinthe meaning of this application, linear is defined as the textile strandhaving at least two ends, which are not connected with one another. Thetextile strand can thereby be curved one or more times in one or moredirections.

In a preferred embodiment, a linearly stretched textile strand forms aspoke of the wheel. The ends of the textile strand are thereby fastenedin the consolidated state to the rim in a positive-locking manner andpreferably also in substance, while the center of the textile strand isdeflected at the hub. Thus, the textile strand forms two partialstrands, which are laterally adjacent to each other in their coursebetween the hub and the rim and without any distance are preferably alsoconnected in substance by means of the matrix material.

In another preferred embodiment the linearly stretched textile strandforms two spokes of the wheel. The ends of the textile strand arefastened in the consolidated state to the rim in a positive-lockingmanner and preferably also in substance, while the center of the textilestrand is deflected at the hub. The two partial strands are separated intheir course between the rim and the hub and form an angle with thereversal point in the hub as vertex.

A fiber composite consists at least one matrix material andreinforcement fibers, which improve the ability of the fiber compositeto withstand stress in the direction of its course. Consolidating orconsolidation is defined here by the fiber composite being hardened.This can occur partially (partial consolidation) or take placecompletely. The fiber composite is unconsolidated when no process ofconsolidation has taken place. During the consolidation, the matrixmaterial hardens and encloses the reinforcement fibers and fixes them intheir position.

Adjacent spokes preferably run at constant angles to one another and areuniformly distributed over the entire circumference of the wheel spider.However, another preferred embodiment also provides spokes, arranged inpairs, with a smaller enclosed angle and a larger angle to the next pairof spokes or vice versa.

In another preferred embodiment, the linearly stretched textile strandforms more than two, but always an even number of spokes. For thispurpose, the ends of the textile strand are fastened in the consolidatedstate to the rim in a positive-locking manner and preferably also insubstance, while it runs from the fastening of the first end to the hub,is deflected there and runs back to the rim. This advantageously takesplace so often until the number of intended spokes is reached. In thisway, the spokes are formed from a single linearly stretched textilestrand. A plurality of linearly stretched textile strands, whereby eachtextile strand or even only some of the textile strands form more thantwo spokes of a rim, is also preferred.

The ends of the textile strands are preferably bent over and follow thecurvature of the rim on its inner side in one of the directions ofrotation. The ends of a plurality of adjacent textile strands preferablyuniformly point towards one another or away from one another.

The linearly stretched textile strands are preferably designed as scrim,knitted fabric, mesh, fabric, or multiaxial textiles. The textilestrands preferably also consist of a plurality of layers, which areadvantageously stitched together or, e.g., held together by means ofadhesive spray.

In an especially preferred embodiment the textile strands are braidedand preferably have a plurality of fiber directions. Preferably, thefibers run at an angle of ±45° to the axis of a spoke. The orientationof the textile strands can be varied over the length, such that the mostfavorable can be provided for the stress. For this purpose, the textilestrands are preferably manufactured in a three-dimensional braidingprocess. Advantageously, textile strands of variable geometry can thusbe produced. The textile strands thus preferably have a greater diameterin the vicinity of the hub and can be divided into two or more partialtextile strands in the area of the fastening to the rim and also thenagain converge into one textile strand.

The textile strands consist of reinforcement fiber material according tothe state of the art. High-strength fiber materials such as glassfibers, carbon fibers or Kevlar (aramid) fibers are preferred.

The hub preferably has an axle hole and/or bolt holes for fastening thewheel. In addition, the hub also preferably has pin-like elevations,around which the textile strands run without interruption and by meansof which the textile strands are deflected. In an especially preferredembodiment, the pin-like elevations are designed, such that on the sidethat is facing the geometric axis of the hub, there is a rounding, aboutwhich the textile strands run, whereby the force is advantageouslydistributed on the entire contact surface by the pin-like elevation andthe textile strand. The part, of the pin-like elevations, which isfacing the rim, runs in its outer surface preferably parallel to theinner surface of the rim. At the site, at which the textile strands passthrough the surface of the pin-like elevations, the pin-like elevationsare somewhat rounded off to avoid a notch effect of the pin-likeelevation on the textile strand. Preferably, the hub has alternatingpin-like elevations with textile strands running about these withoutinterruption and pin-like elevations without textile strands. Only everysecond pin-like elevation thus holds a textile strand, whereby due tothe pin-like elevations being arranged between them, the impression of aclosed hub surface in the direction of the inner side of the rim isachieved, however. In a preferred embodiment the hub has only pin-likeelevations, which also hold textile strands, while the intermediatespaces between the pin-like elevations with the textile strands runningaround them are filled with hub material.

The hubs preferably have a two-part design. There is preferably a firsthub part with a plate-shaped lower blade end, which optionally has,besides the axle opening and/or bolt openings, also pin-like elevationswith a height, which corresponds to the width of the textile strands.The second hub part then has only optionally an axle opening and/or boltopenings and is positioned on the first hub part and fixed there. Thetextile strands running about the pin-like elevations are advantageouslyaxially fixed and secured against shifting in this way. The bolt holespreferably run through the pin-like elevations.

Another preferred hub shape provides for the linearly stretched textilestrands to be led only through recesses in the hub material. An axialslipping is prevented by means of flat, preferably circular-disk-shapedlimitations of the hub parts, which are arranged above and below theserecesses. After the consolidating of the linearly stretched textilestrands and the mounting of the rim, the linearly stretched textilestrands are fixed in a positive-locking manner and optionally also insubstance via the matrix material. The hub parts optionally have an axleopening and/or bolt openings.

Another preferred embodiment of the hub provides for manufacturing firstand second parts of the hub. Each hub part thereby has, besides theoptional axle opening and/or the optional bolt openings, some of thepin-like elevations. In a preferred embodiment, 50% of the number of thepin-like elevations are arranged on the first hub part and 50% on thesecond hub part. In another preferred embodiment, each hub part haspin-like elevations with half of the overall height, such that thepin-like elevations are available in their needed overall height afterjoining the two hub parts together. It is obvious to the person skilledin the art that, when the number of pin-like elevations is not an evennumber, he distributes the pin-like elevations as uniformly as possible,e.g., alternating on the two hub parts. It is also obvious that, whenthe height of a pin-like elevation of a hub part is 30% of the necessaryoverall height of the pin-like elevation, a pin-like elevation on theother hub part with a height of 70% of the overall height standsopposite this hub part. The overall height of the pin-like elevationsbetween the two hub parts corresponds to the width of the textile strandthat runs around them. Likewise, the free space, which runs around thepin-like elevations through the material of the hub, corresponds to theheight of the circulating textile strand.

The two hub parts are preferably fixed by bolting or by these being heldtogether via the bolt holes during the mounting of the wheel. In apreferred embodiment, the hub also consists of fiber composite and thetwo hub parts are joined together in the course of the consolidation ofthe fiber composite and held in substance via the matrix material.

The hub preferably consists of material that is known from the state ofthe art for such purposes. This may be, e.g., deep-drawing steel,aluminum, magnesium, or light metal alloys. However, fiber-reinforcedplastic is also preferably used.

The rim of the wheel consists, in a preferred embodiment, of fibercomposite. Especially preferred here is a multilayer braided fiberreinforcement. The wheel spider is fastened preferably by the ends ofthe linearly stretched textile strands and, if present, the sections ofthe linearly stretched textile strands, which run along the inner sideof the rim, being braided over and thus extending into the rim in theconsolidated state, without, however, fibers from the fiber strands ofthe wheel spider passing over into fibers of the fiber reinforcement ofthe rim. After the consolidation of the rim, the ends of the textilestrands and the parts of the textile strands running along the innerside of the rim are fixed in a positive-locking manner and optionallyalso in substance via the matrix material in the rim body.

Another preferred embodiment provides for the rim to have, in its innercircumference, beads, into which the ends of the linearly stretchedtextile strands and, if present, the sections of the linearly stretchedtextile strands, which run along the inner side of the rim, extend, andin which these are consolidated. In this way, a wheel spider made offiber composite can advantageously be fastened in a metal rim in apositive-locking manner.

Another preferred embodiment provides for each linearly stretchedtextile strand to form two spokes and for each of the two ends of thetextile strand to be divided into two single ends.

In a first embodiment, the single ends are divided (preferably at 50% ofthe material thickness) in a plane parallel to the axis of the wheel.They are spread apart on the inner side of the rim and form thepositive-locking connection between the wheel spider and the rim afterthe consolidating. After the spreading apart, the two ends follow thecurvature of the rim on the inner side thereof in the and against thedirections of rotation of the wheel. A molding can advantageously beinserted into the V-shaped section between the two ends forstabilization. This molding is preferably formed by a lost core. Themolding preferably consists of foam material.

A second preferred embodiment provides for the single ends to be dividedin a plane vertical to the axis of the wheel (also preferably at 50% ofthe material thickness of the textile strands). The ends then embrace apart of the inner side of the rim in both axial directions and followits contour. After the consolidating of the textile strands, the rim isthus held in a positive-locking manner by means of the ends of allspokes. This embodiment is advantageously suitable for use with metalrims. A formation of beads in the rim material is advantageously notnecessary here.

A preferred process for manufacturing linearly stretched textile strandsprovides for manufacturing them by braiding. A 3D braiding machine isadvantageously used here. The linearly stretched textile strands can bemanufactured as a continuous product and thereby also be provided withvariable cross sections, thickenings, splittings and joinings. For thispurpose, the desired wheel size is taken into consideration already whenmanufacturing the linearly stretched textile strands. The linearlystretched textile strands are then cut to the necessary length and areavailable for further processing.

Either

a) consolidated or

b) unconsolidated

prepared linearly stretched textile strands are used for furtherprocessing.

According to a), unconsolidated textile strands are inserted into a moldwhich specifies the intended curvature and other shaping of the textilestrands and is then saturated with matrix material, or if the matrixmaterial is contained in the textile strands, hardens this matrixmaterial. Thermoplastic or duroplastic material is used as the matrixmaterial. Polypropylene is especially preferred as thermoplasticmaterial and epoxy resin is especially preferred as duroplasticmaterial. The consolidated textile strands are then inserted into a moldwhich already contains the first hub part. Preferably, the ends of thetextile strands extend into the rim area. The second hub part is theninserted, and the mold is closed. The rim area is then formed by themold being braided over. The rim area is then also consolidated. Thetextile strands between the hub and the rim are now fixed in apositive-locking manner.

According to b), unconsolidated textile strands are inserted into a moldfor the rim, which already contains the first hub part. The second hubpart is then inserted and the mold is closed. The mold now reproducesthe contour of the rim in the outer area. The ends of the textilestrands preferably extend into the rim area. Subsequently, the rim moldis braided over. After the braiding process, the entire objectconsisting of the hub, textile strands and rim is consolidated.

Besides the braiding over of the mold for forming the rim, other methodsfor fiber deposition known from the state of the art are alsoadvantageously used. Winding as well as the deposition of prepregs madeof fiber material are especially preferred here.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a wheel;

FIG. 2 is a perspective view of a mold and a spoke segment;

FIG. 3 is an exploded view of a mold half, a hub part and preformedspoke segments;

FIG. 4 is an exploded view of mold halves, a hub part and preformedspoke segments;

FIG. 5 is a cross sectional view of the wheel spider of FIG. 5;

FIG. 6 is a cross sectional view of the wheel spider of FIG. 5;

FIG. 7 is a sectional view of the wheel spider of FIG. 6;

FIG. 8 is an enlarged view of another embodiment of a wheel spider;

FIG. 9 is an enlarged view of the detail A of FIG. 8;

FIG. 10 is a perspective view of another embodiment of a wheel;

FIG. 11 is a cross sectional view of the wheel of FIG. 10;

FIG. 12 is an enlarged cross sectional view of FIG. 11;

FIG. 13 is an enlarged cross sectional view of FIG. 12;

FIG. 14 is an exploded view of textile strands together with a mold partfor a hub;

FIG. 15 is a view of a three-dimensional braiding machine; and

FIG. 16 is an enlarged view of the three-dimensional braiding machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, FIG. 1, FIG. 2, FIG. 3, FIG. 4,FIG. 5, FIG. 6 and FIG. 7 show one embodiment of the present invention.A wheel spider is constructed from individual, preformed spoke segments(2). The spoke segments (2) are shaped here in separate molds (4), inwhich the lengthwise stretched textile strand is draped. It is possible,in this case, to consolidate the spoke segments (2) in advance. Thefirst hub part (3 a) as well as the preformed spoke segments (2) arethen inserted into the insertion grooves (7) of the first mold half (5)of the mold. After the second hub part (3 b) is applied and the moldhalves (5, 8) are closed, the formation of the rim well (1) takes placeby braiding over the molds (5, 8) acting as a braiding core (6). Thespokes (2) are thereby integrated axially and radially via a positivelocking into the textile structure of the rim well (1). A multipartouter mold is used in the area of the rim well (1) for pressing thetextile preform during the consolidation. After the consolidation, thewheel spider and rim well are connected in a positive-locking manner andin substance.

FIG. 8 and FIG. 9 show another embodiment of the present invention. Thespokes (2) of the wheel spider are formed by draping the unconsolidatedlengthwise stretched textile strand in the mold half 1 of the rim mold,as well as the wheel hub half 1 inserted therein. In order to guaranteean as large as possible connecting area between the spokes and the rimwell, a spreading apart, on both sides, of the ends of the textilestrand used for the spokes in the area of the rim well takes place here.The V-shaped recess formed here between the spread-apart textile layersis closed by means of a wedge-shaped inlay. After the wheel hub half 2is applied and the mold halves are closed, the formation of the rim welltakes place by braiding over the mold acting as a braiding core. Thespokes are thereby axially and radially integrated via a positivelocking formed in an undercut area into the textile structure of the rimwell. A multipart outer mold is used in the area of the rim well forpressing the textile preform during the consolidation. After theconsolidation, the wheel spider and rim well are connected in apositive-locking manner and in substance.

FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15 and FIG. 16 showyet another embodiment of the present invention. The connection of thelengthwise stretched textile strand to the rim well takes place by meansof a positive locking formed in an undercut area, whereby the textileextends axially over the well as well as the outer flange geometry ofthe rim well. FIG. 14 shows how the lengthwise stretched textile strandstogether with a mold part for the hub are draped in the mold.

FIG. 13 illustrates how the fiber course of the fibers (a-f) passesover, without interruption, from the one-part central section into thespread-apart end of the textile strand. In the undivided section of thetextile strand, the fibers here run at angles of +45° (e, c, e) as wellas −45° (b, d, f) to the axis of the textile strand. After the dividingand spreading apart, the first part has the fibers b, d and e and thesecond partial strand has the fibers a, c and f. In addition, the fibersalso run after the dividing at angles of ±45° to the axis of therespective partial strand.

The lengthwise stretched textile strands of the spoke segments havedifferent cross sections, which are used for a shaping of the wheelspider corresponding to stress. The preforming of the spoke segmentswith different cross sections as well as the spreading of the spoke endsinto two fiber strands (2 a, 2 b) each is achieved by means of a 3Dbraiding machine (FIG. 15). This makes it possible to manufacture acontinuous 3D textile, which consists of a plurality of spoke segmentsstrung together, which are separated from one another by means of aseparating device according to the state of the art (e.g., lever shears,automatic cutter) (FIG. 16 as a magnification of detail C of FIG. 15).

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A process for manufacture of a wheel with a wheelspider, whose spokes comprise one or more linearly stretched textilestrands as reinforcement material of a fiber composite, the processcomprising: preparing a mold corresponding to a rim contour having afirst mold part and a second mold part, which has recesses for formingthe wheel spider; preparing unconsolidated linearly stretched textilestrands; inserting a first wheel hub part into the first mold part, suchthat a continuous course of a shape of spoke segments is imaged;inserting the unconsolidated linearly stretched textile strands into thefirst mold part, such that at least ends of the linearly stretchedtextile strands are integrated into the first mold part in an undercutarea and the linearly stretched textile strands extend through the hub;inserting the second hub part; closing the mold by joining the firstmold part and the second mold part together; forming a reinforcementfiber structure of the rim by means of further deposition of fibers ontothe mold; joint consolidating the rim and the wheel spider; removing thewheel from the mold.
 2. A process for manufacture of a wheel with awheel spider, whose spokes comprise one or more linearly stretchedtextile strands as reinforcement material of a fiber composite, theprocess comprising: preparing a mold corresponding to a rim contourhaving a first mold part and a second mold part, which has recesses forforming the wheel spider; preparing the linearly stretched textilestrands; inserting a first wheel hub part into the first mold part, suchthat a continuous course of a shape of spoke segments is imaged;inserting already consolidated or pre-consolidated linearly stretchedtextile strands into the first mold part, such that at least ends of thelinearly stretched textile strands are integrated into the first moldpart in an undercut area and the linearly stretched textile strandsextend through the hub; inserting the second hub part; closing the moldby means of joining the first mold part and the second mold parttogether; forming a reinforcement fiber structure of the rim by means ofdeposition of fibers onto the mold; joint consolidating the rim and thewheel spider; removing the wheel from the mold.
 3. A process formanufacture of a wheel with a wheel spider, the process comprising:providing a rim; forming a wheel spider having a hub and spokes, saidspokes comprising one or more textile strands as reinforcement materialof a fiber composite and each of said one or more textile strandsextending at least once from said rim to said hub and back withoutinterruption to form at least one of said spokes, said one or moretextile strands having ends, which diverge from each other and arespread apart from each other; fastening said one or more textile strandsto one of said rim and a well of the wheel via a positive-lockconnection, said positive-lock connection comprising one of at least aportion of said rim and at least a portion of said well.
 4. A process inaccordance with claim 3, wherein said ends are joined to a contour of aninner side of the rim in an axial direction following the rim, saidpositive-lock connection comprising said inner side of said rim.
 5. Aprocess in accordance with claim 3, wherein each of said one or moretextile strands extends around pin-like elevations in said hub.
 6. Aprocess in accordance with claim 3, wherein said one or more textilestrands extends through at least one recess in said hub, said one ormore textile strands being connected to said hub via another positivelock connection, said another positive lock connection comprising saidat least one recess.
 7. A process in accordance with claim 3, whereinsaid ends are positively locked in two directions of rotation of thewheel in said well via said positive-lock connection, at least one ofsaid one or more textile strands forming more than two spokes and, onesection of said at least one of said one or more textile strands, whichis not identical with ends, extends in an inner surface of the well andending with the well.
 8. A process in accordance with claim 3, whereinat a site, at which one end of each of said one or more textile strandsis spread apart, a free space having a triangular cross section, intowhich an ideally shaped molding is inserted, is formed.
 9. A process inaccordance with claim 5, wherein said spokes and said hub are connectedvia another positive-lock connection, said another positive connectioncomprising said pin-like elevations.